TEHRAN (INIC)- Researchers at Sharif University of Technology have come up with the technical know-how for the production of highly strong nano-alloys by rapid solidification method.

The alloy is hypereutectic and based on nano-structural aluminum. Thanks to their low weight and more desirable physical/chemical properties, they will have vast applications in transportation and auto industry.

Mohammad Rajabi prepared hypereutectic nano-alloys of aluminum-silicon through two methods of melt-spinning and gas atomization and examined their microstructures and composing phases by optical microscope, XRD, SEM and TEM.

In the next step, ground powders and ribbons, after initial pressing, were cooled, de-gassed and hot-pressed orderly and their mechanical properties were evaluated at various temperatures. In the final step, the properties of alloys produced by rapid solidification and those prepared by the traditional casting method were compared. Moreover, feasibility study of in-engine lining was conducted.

"The use of rapid solidified alloys would lead to betterment of mechanical properties, especially at high temperatures, as well as reduction of thermal expansion coefficient compared to the available casted alloys. This effect is caused by the refinement of microstructures, formation of nanometric phases and extended component saturation limit in aluminum based alloys," Rajabi went on explaining about the outcomes of the research.

"For instance, rapid solidified alloys can improve mechanical strength (at 573K) up to 58% and thermal conductivity up to 21%,” he added.

Detailed information on this research work is available at the Journal of Materials Characterization, volume 60, pages 1370 to 1381, 2009.